Safe-Lock Protection: GFCI safety is improved. When miswired, these GFCI outlets have no power and can't be reset, making them safer than conventional receptacles.

These GFCI feature an end-of-life monitoring function; They can't reset correctly when GFCI reaches the end of life.

Improved resistance to surge and corrosion.

*UL943 Standard Improvements:

Auto-Monitoring or Self-Test Function.This Function allows for periodic, automatic testing of the ability of the GFCI to respond to a ground fault. If the Self-Test Function detects a problem, the GFCI must deny power or provide visual and/or audible indication.

Reverse Line-Load Misfire Function.If the line cable is wired to the load terminals of a receptacle GFCI, power to the receptacle face will be denied. This requirement applies to the initial installation and any subsequent reinstallation.